1. Field of the Invention
The present invention relates to a data transfer network in which a plurality of nodes is connected.
The data transfer network of the present invention can be applied to networks in general, such as the general Internet, public communication networks, company-internal communication networks, LAN, computer networks, distributed computer networks, distributed router networks, exchange networks, switch networks that are used in devices that perform data communications such as routers and so forth, data communication networks that link CPUs, memory, and so forth, and data communication networks in LSI such as CPU, for example.
2. Description of Related Art
Data transfer networks in which a plurality of nodes is connected that perform distributed processing to respective nodes include (A) bus networks, (B) ring networks, (C) hub networks (star-shaped networks), (D) full mesh networks, (E) hyper expanded (hypercube) networks, and so forth. A hypercube network is a hyper structure network that comprises a bus network or ring network as a plurality of local networks (sub-networks).
Furthermore, it is considered that, in the future, the number of terminals contained in data transfer networks will increase and that data transfer speeds will increase. Hence, it is important to increase the amount of data (traffic) that can be processed by the whole network, that is, to raise the traffic capacity. It is therefore necessary to investigate optimization and increased efficiency and so forth of the network configuration.
The capacity of the five types of network above will be described with reference to FIGS. 12 to 14.
FIG. 12 shows the relationship between the numbers of nodes contained in the respective networks and the effective node number. The effective node number indicates the traffic that can be processed by the whole network with the number of nodes serving as the units.
FIG. 13 shows the relationship between the number of nodes contained in the respective networks and the required link number. The required link number is the number of connections between nodes required in order to configure the network.
FIG. 14 shows the relationship between the number of nodes contained in the respective networks and the available maximum node capacity. The available maximum node capacity indicates the processing power of the nodes for which the required processing power is maximum among the nodes contained in the network. FIG. 14 shows the available maximum node capacity in arbitrary units.
As shown in FIG. 12, when the networks are configured by using the same numbers of nodes, the effective node number grows smaller in order starting with the full mesh network as the largest, followed by the hub network, the hypercube network, the ring network, and then the bus network.
However, in a full mesh network, one node is connected to all of the other nodes. As a result, as shown in FIG. 13, the required link number is huge in comparison with the links required in networks of other configurations.
On the other hand, in hub networks, signals from all the nodes pass through a relay device at the core of a star shape. Hence, as shown in FIG. 14, the available maximum node capacity has a huge value in comparison with networks of other configurations.
Conventionally, when distributed processing has been performed in the whole network by a plurality of nodes, a hypercube network has been adopted. In a hypercube network, the required link number is smaller than in a full mesh network, the available maximum node capacity is smaller than that of a hub network, a ring network, and a bus network, and the effective node number is larger than that of a ring network and a bus network. In a hypercube network, the number of local networks of which a certain node is an element is expressed as the order. In the case of a conventional hypercube network, the order is three or four. Although the effective node number increases when a higher-order hypercube structure rendered by raising the order (m) is used, the required link number (=2×m) also increases. Further, in cases where the nodes gradually increase, the initial number of nodes is often small. In a hypercube network, there is the problem that the efficiency drops when the number of nodes is small. In addition, as shown in FIG. 12, when 400 nodes are used, the effective node number is only 12 in a fifth-order hypercube network containing bus network as a local network. Therefore, this is hardly adequate in comparison with the 200 nodes of a complete mesh network and the 133 nodes of a hub network.
As a result, a new data transfer network with a higher than conventional overall evaluation from various perspectives such as the effective node number, the required link number, and the available maximum node capacity is desirable.